The FBIOPUT_CON2FBMAP ioctl takes a console_lock(). When this is called
while nouveau was runtime suspended, a deadlock would occur due to
nouveau_fbcon_set_suspend also trying to obtain console_lock().
Fix this by delaying the drm_fb_helper_set_suspend call. Based on the
i915 code (which was done for performance reasons though).
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Peter Wu <peter at lekensteyn.nl>
---
Tested on top of v4.7-rc5, the deadlock is gone.
---
drivers/gpu/drm/nouveau/nouveau_drm.c | 4 +--
drivers/gpu/drm/nouveau/nouveau_drv.h | 1 +
drivers/gpu/drm/nouveau/nouveau_fbcon.c | 54 ++++++++++++++++++++++++++++-----
drivers/gpu/drm/nouveau/nouveau_fbcon.h | 2 +-
4 files changed, 50 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c
b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 11f8dd9..f9a2c10 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -552,7 +552,7 @@ nouveau_do_suspend(struct drm_device *dev, bool runtime)
if (dev->mode_config.num_crtc) {
NV_INFO(drm, "suspending console...\n");
- nouveau_fbcon_set_suspend(dev, 1);
+ nouveau_fbcon_set_suspend(dev, FBINFO_STATE_SUSPENDED, true);
NV_INFO(drm, "suspending display...\n");
ret = nouveau_display_suspend(dev, runtime);
if (ret)
@@ -635,7 +635,7 @@ nouveau_do_resume(struct drm_device *dev, bool runtime)
NV_INFO(drm, "resuming display...\n");
nouveau_display_resume(dev, runtime);
NV_INFO(drm, "resuming console...\n");
- nouveau_fbcon_set_suspend(dev, 0);
+ nouveau_fbcon_set_suspend(dev, FBINFO_STATE_RUNNING, false);
}
return 0;
diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h
b/drivers/gpu/drm/nouveau/nouveau_drv.h
index 822a021..a743d19 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drv.h
+++ b/drivers/gpu/drm/nouveau/nouveau_drv.h
@@ -147,6 +147,7 @@ struct nouveau_drm {
struct nouveau_channel *channel;
struct nvkm_gpuobj *notify;
struct nouveau_fbdev *fbcon;
+ struct work_struct fbdev_suspend_work;
struct nvif_object nvsw;
struct nvif_object ntfy;
struct nvif_notify flip;
diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index d1f248f..089156a 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -492,19 +492,53 @@ static const struct drm_fb_helper_funcs
nouveau_fbcon_helper_funcs = {
.fb_probe = nouveau_fbcon_create,
};
+static void nouveau_fbcon_suspend_worker(struct work_struct *work)
+{
+ nouveau_fbcon_set_suspend(container_of(work,
+ struct nouveau_drm,
+ fbdev_suspend_work)->dev,
+ FBINFO_STATE_RUNNING,
+ true);
+}
+
void
-nouveau_fbcon_set_suspend(struct drm_device *dev, int state)
+nouveau_fbcon_set_suspend(struct drm_device *dev, int state, bool synchronous)
{
struct nouveau_drm *drm = nouveau_drm(dev);
- if (drm->fbcon) {
- console_lock();
- if (state == FBINFO_STATE_RUNNING)
- nouveau_fbcon_accel_restore(dev);
- drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
+ if (!drm->fbcon)
+ return;
+
+ if (synchronous) {
+ /* Flush any pending work to turn the console on, and then
+ * wait to turn it off. It must be synchronous as we are
+ * about to suspend or unload the driver.
+ *
+ * Note that from within the work-handler, we cannot flush
+ * ourselves, so only flush outstanding work upon suspend!
+ */
if (state != FBINFO_STATE_RUNNING)
- nouveau_fbcon_accel_save_disable(dev);
- console_unlock();
+ flush_work(&drm->fbdev_suspend_work);
+ console_lock();
+ } else {
+ /*
+ * The console lock can be pretty contented on resume due
+ * to all the printk activity. Try to keep it out of the hot
+ * path of resume if possible. This also prevents a deadlock
+ * with FBIOPUT_CON2FBMAP.
+ */
+ WARN_ON(state != FBINFO_STATE_RUNNING);
+ if (!console_trylock()) {
+ schedule_work(&drm->fbdev_suspend_work);
+ return;
+ }
}
+
+ if (state == FBINFO_STATE_RUNNING)
+ nouveau_fbcon_accel_restore(dev);
+ drm_fb_helper_set_suspend(&drm->fbcon->helper, state);
+ if (state != FBINFO_STATE_RUNNING)
+ nouveau_fbcon_accel_save_disable(dev);
+ console_unlock();
}
int
@@ -526,6 +560,8 @@ nouveau_fbcon_init(struct drm_device *dev)
fbcon->dev = dev;
drm->fbcon = fbcon;
+ INIT_WORK(&drm->fbdev_suspend_work, nouveau_fbcon_suspend_worker);
+
drm_fb_helper_prepare(dev, &fbcon->helper, &nouveau_fbcon_helper_funcs);
ret = drm_fb_helper_init(dev, &fbcon->helper,
@@ -571,6 +607,8 @@ nouveau_fbcon_fini(struct drm_device *dev)
if (!drm->fbcon)
return;
+ flush_work(&drm->fbdev_suspend_work);
+
nouveau_fbcon_accel_fini(dev);
nouveau_fbcon_destroy(dev, drm->fbcon);
kfree(drm->fbcon);
diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.h
b/drivers/gpu/drm/nouveau/nouveau_fbcon.h
index ca77ad0..34b2504 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.h
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.h
@@ -66,7 +66,7 @@ void nouveau_fbcon_gpu_lockup(struct fb_info *info);
int nouveau_fbcon_init(struct drm_device *dev);
void nouveau_fbcon_fini(struct drm_device *dev);
-void nouveau_fbcon_set_suspend(struct drm_device *dev, int state);
+void nouveau_fbcon_set_suspend(struct drm_device *dev, int state, bool
synchronous);
void nouveau_fbcon_accel_save_disable(struct drm_device *dev);
void nouveau_fbcon_accel_restore(struct drm_device *dev);
--
2.8.3
